06 Trailblazer SS no crank/no start diagnostics

[tek95969]

Just joined this forum and I'm also on a few SS forums. Bought this truck new and have been plagued with this problem and always have gone the ignition switch route replacing at least 6! Two under warranty 4 doing it myself. Gets it going and starts regularly for up to a year maybe and then the gremlins return.
So hears what I get after doing a test at the fuseblock

On the fuse block - starter relay #86 gets a weak light. # 87 strong

testing ground request - nothing

jumping #30 and 86 starter cranks

If the starter attempts to crank when jumping does that rule out the starter completely?
AND where do I go next?

Thanks for your time and any help you can offer,

 

[Mooseman]

What brand switch are you using? Have heard that aftermarket switches don't last so better to stay with ACDelco.

Have a look at this brand new article on how to rebuild/clean the ignition switch. Could give it a try, costs nothing.

Sounds like your starter is fine. Have you tried swapping the starter relay with another one? Sounds like the PCM is not sending the signal to the relay.

Welcome to GMTN!

 

[tek95969]

Thanks!
The switch is a Borg Warner in there now but I've had both. O'Reiley Auto Parts gives a lifetime warranty on the switch so the last few times I've swapped the old one for a new one. The AC Delco switch had to be ordered. But here's the best part - I go out in the morning after testing it last night, put the starter relay back in and it fires up after being dead for days. Shut it down and no crank/no start again. Tried to jump starter again but this time nothing happens, no crank, nothing.
Guess I'm going to check the switch next with the spares I have that I know are good.

 

[BlazingTrails]

There are several grounds under the hood that need to be cleaned.

Driver side fender wall there are 2
One is buy the fuse block and one by the battery

Passenger fender wall

Driver side strut tower

Passenger floor board under the carpet below the radio.

Tale them lose, sand everything clean, put them back together.

2 of those grounds will cause a no start condition!

IF that does not get it remove the knee bolster and inspect the main harness plug under the steering colum.

 

[tek95969]

Awesome Gingerbread Man! Knowing these are located is half the battle.
I'll be testing tonight and will keep you posted.

tek

 

[gmcman]

Along with what BlazingTrails stated, since the common denominator is the ignition switch..I would look closely on what's downstream of the ignition switch to verify nothing is drawing excess current. This could be the cause of a bad ground, also assuming the battery, starter and solenoid are in good shape.

Electrical problems are a pita, I feel your pain. Since you don't know the history of the vehicle not being the original owner, I would go over the entire path starting with the battery to rule out any coincidences.

Check battery terminals, they should not move, check inside to ensure the teeth are contacting the lead of the battery. Check the terminals at the starter solenoid

Does it have an aftermarket stereo or more important, alarm with remote start?

 

[BlazingTrails]

I also wanted to ad to what I said earlier, when you clean the grounds make sure you go all the way through the primer to clean metal. The primer is gray and can fool you into thinking it is bare metal.

For some reason all of these critical ground points are bolted to a painted surface, GM is solely relying on the threads of the bolt for the ground connection which is a bad judgement call IMO. It would also be great if you treated the area with dielectric grease prior to bolting the wires back down to keep the connection from getting corroded again.

Good luck man, these things can get frustrating some times.

 

[tek95969]

Excellent idea and will do with the grease. Going through it one by one and cleaning them all.
Will keep you posted...

 

[Knucklehead]

We Had similar problems on our 06.

It would start and run then out of no where, it wouldn't crank at all sometimes it would crank but no start.

We get stuck places and sometimes it would take us awhile to finally get it to start. We starting replacing parts. Swapping relays... It took us almost a year to finally get it right.

After swapping relays we noticed it had something to do with them. The relays were getting really hot. So we started poking a round under the fuse box. Took it all apart clean it all up sprays it down with wd40 and every electrical problem went away.

Lights, headlights, starter, interior problems etc

 

[tek95969]

Well I cleaned the 3 grounds under the hood by taking each off, grinding down the paint at connection point, ground the surface of connector, applied dielectric grease. Ground on the strut tower harder to get to without pulling wheel so I sprayed it down with brake cleaner.
And still no crank!! Damn!!
Decided to fool around with ignition switch and replaced it with a spare I had. Turn the key and boom it fires up.
Repeatedly shut down and restarted and so far has been behaving.
Problem is I didn't really isolate the problem just got it started but I'm hoping the clean grounds played a part.

Big thanks to Blazing Trails and GMC man for your input.
This forum has some amazing people on it who know their stuff.

 

[BlazingTrails]

Your welcome brother! We are glad you are here

 

[tek95969]

Update to 06 no crank/ no start problems.

So I get it going after cleaning all the grounds under the hood and still nothing, I decide to swap the switch with one of my good spare switches and get it going.
Get down to LA area and it dies again, day of my brother-in-laws funeral. Put a switch in from the dealer and resurrect it AGAIN.
More trouble this week after getting back and things aren't any better - repeated attempts to start it, sometimes getting it going. NEW SYMPTON: Started up my street after getting it going once and it completely died three houses down. Pulled over, cranked the key a few times and it fired up. Decide to drive it around and it dies again as I'm turning in my street- same thing, pull over, crank it a few times and it starts.
I was able to get the motor to crank by jumping it at the relay point on the fuse block using May03LT methods

 

[BlazingTrails]

I have 3 thoughts, 1 how are you lining up the gear on the ignition switch? 2 there is a ground wire that goes directly from the battery to the engine block, did you clean that ground? 3 behind the knee bolster there is a large connector it should be white. Inspect it and unplug it to make sure nothing is burnt there.